CpG-ODN Augments Cytokines Release of Cultured Nasal Epithelial Cells: A Model of Chronic Rhinosinusitis with Acute Exacerbation
Date Issued
2010
Date
2010
Author(s)
Lin, Chih-Feng
Abstract
Background :
Chronic rhinosinusitis (CRS) is defined as inflammation and infection involving the nasal mucosa and the adjacent sinus cavities. Clinically, the patients with CRS may suffer from symptoms of mucopurulent discharge, nasal obstruction, facial pain, and hyposmia. Antibiotics, saline irrigations, steroids, and anti-leukotrienes may be given for symptoms relief. However, episodes of recurrence or acute exacerbation occurred to these patients, and caused some irreversible changes in airway structure and function. The pathophysiology of frequent acute exacerbation in these patients is still unclear, making treatments particularly challenging.
CpG-ODN refers to sequences that include an unmethylated cytosine and guanosine ,which are relatively common in the genomes of most bacteria and DNA viruses. CpG-ODN had been implicated as a major structural component of bacterial biofilm, and contributed to the persistence of chronic infection. Clinically, recalcitrant CRS is associated with biofilm formation, and biofilm may cause the unfavorable outcomes of surgery for CRS. However, the molecular significance of CpG-ODN in CRS is still unclear. We aim to investigate the immune-modulation effects of CpG-ODN ,and elucidate the role of biofilm in CRS.
Hypothesis :
1.The existence of CpG-ODN may maintain a low profile of cytokines production in the sinus mucosa, and play a role in the persistence of inflammation in chronic rhinosinusitis.
2.During CRS with acute exacerbation, CpG–ODN synergistically up-regulate the immuno-reactions of pro-inflammatory mediators, augments intranasal cytokines release, and contribute to the complications and severity of CRS with acute exacerbation.
Materials and Methods:
Twenty patients who are diagnosed as CRS and underwent surgery were included prospectively. None of them receives any treatment at least one month before operation. The one who has atopy, asthma, or allergic rhinitis was previously excluded. The nasal epithelial cells harvested from nasal polyps were collected for ALI (air-liquid interface) culture. At the end of culture (Day 20 after confluence), CpG-ODN , IL-1β , and TNF-α were added in single regimen or in combination to stimulate the nasal epithelial cells. After 24 hours-treatment, the culture medium of each well was collected and immediately stored at -80℃for later IL-6,IL-8 and MCP-1 measurement using ELISA.
Statistical analysis :
The paired samples test was used for evaluation of differences between experiments and controls. ANOVA was used when there is a multiple sample comparison. P values less than 0.05 was considered significant.
Results :
1.A model mimicking the in vivo microenvironment of stable CRS was created.
2.Intrinsic IL-1β and TNF-α levels were undetectable in this model, and IL-6 ,
IL-8 ,MCP-1 levels were detectable during 21-days culture period, with a trend toward
homogeneity .
3.Extrinsic IL-1β and TNF-α were used to stimulate the cultured nasal epithelial cells, to initiate a condition resembles CRS with acute exacerbation. IL-1βinduced IL-6,IL-8 and MCP-1 expressions in a dose-dependent fashion, while TNF-α only induced these cytokines release insignificantly.
4. CpG–ODN induced MCP-1 expression with a dose-dependent fashion, but not in IL-6 and IL-8.
5. CpG-ODN synergistically potentiate IL-6,IL-8, and MCP-1 release in the presence of IL-1 β and TNF-α.
Conclusion :
CpG-ODN is associated with the chronicity of CRS. Elimination of such substances in the management of CRS is mandatory. CpG-ODN augments intranasal cytokines release in patients with acute exacerbated sinusitis. Strategies such as local debridement or short-term immuno-suppressants are needed to stop the vicious circle.
Subjects
chronic rhinosinusitis
acute exacerbation
nasal epithelial cells
cytokines
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